The present invention relates to a structural bearing assembly, in particular a lubricated structural bearing assembly which might be used for example as a bridge bearing.
Structural bearings having a sliding layer of polytetrafluoroethylene (PTFE) are known. These are generally used in conjunction with a stainless steel contact plate or possibly a second PTFE surface. Frequently, these are lubricated by providing dimples in the PTFE surface and filling these dimples with lubricant.
It has been observed that such bearings have sometimes resulted in difficulties particularly when the total cumulative movement between the sliding surfaces is large. In some instances, the lubrication effect is reduced leading to high friction between the sliding surfaces.
In utilising plastics materials such as PTFE, the problem of cold flow of the material under load can present problems if the lubricant is diminished. In the case of PTFE this danger exists since, the lubricating channels in the bearing surfaces can become blocked due to cold flow as the lubricant is depleted.